The redox states of freeze trapped corneas in normal, biochemically altered, and pathological states will be studied by precise measurements of the naturally fluorescent pyridine nucleotide and flavoprotein components of corneal mitochondria, with special emphasis on differences of redox states between the endothelial and epithelial layers of the cornea. A variety of biochemical and physiological perturbations will be imposed upon the cornea by pathological states in situ, by perfusion with inhibitors and with substrates in vitro, and by perturbations of active transport in vivo and in vitro. In addition, corneas with a wide range of trauma and pathological states including the effects of soft, hard, and gas permeable contact lenses will be studied with the ultimate goal of using the precise data the freeze trapped, normal and abnormal cornea from animals as a basis for the controlled study of perifused corneas by flavin and pyridine nucleotide fluorometry at room temperature and ultimately in vivo. Collaboration of two basic science laboratories and clinical expertise is proposed.